build(deps): bump next from 15.5.15 to 15.5.18

Bumps [next](https://github.com/vercel/next.js) from 15.5.15 to 15.5.18.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v15.5.15...v15.5.18)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 15.5.18
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package.json

@@ -26,7 +26,7 @@
     "javascript-time-ago": "^2.6.4",
     "lucide-react": "^0.548.0",
     "marked": "^18.0.3",
-    "next": "^15.5.15",
+    "next": "^15.5.18",
     "react": "^19.2.5",
     "react-dom": "^19.2.5",
     "react-ga": "^3.3.1",